Efficient nitrogen recovery from domestic wastewater through struvite precipitation: Optimizing process parameters and characterization analysis

Recovery of nitrogen from domestic wastewater through struvite precipitation enables the circular economy with revenue generation to treatment plants. Struvite formation factors (pH, magnesium mass, and reagent type) were investigated in the present study. Struvite is formed via a reaction involving NH₄⁺-N, Mg, and P. Magnesium sources (MgCl₂, MgSO₄, MgO), pH (5–11), and magnesium mass (0.5–1.25 g) were identified using response surface methodology (RSM). The optimal condition was pH 8.53 with 1.13 g MgO, resulting in 97.0 % NH₃-N removal and 2.66 g struvite production. The quality of struvite was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR), indicating an irregular rod-shaped morphology, 12.2 nm crystalline size, and 98.9 % crystallinity. The findings highlight the necessity to enhance nitrogen recovery efficiency for large-scale wastewater treatment considering the future potential of struvite.